dark
off-the-record
mum
crypto-
secretomal
secernent
closehanded
occulted
top secret
under wraps
subterranean
on the down-low
under the covers
make known
pseudosecret
supersecret
spill the beans
secretomics
on the hush
closehandedness
latently
exposure
secret of Polichinelle
something nasty in the woodshed
ultrasecret
hidness
divulgation
underwrapped
concealment
confidence
darkness
keep a lid on
ectocrine
incretion
occult
out
in petto
underhand
cryptadia
clandescent
secret
secretive
underhanded
nonsecret
hiding
concealing
tip one's hand
covert
let the cat out of the bag
backstage